# std::pmr::polymorphic_allocator<T>::new_object

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< cpp‎ | memory‎ | polymorphic allocator

template< class U, class... CtorArgs > U* new_object( CtorArgs&&... ctor_args ); |  | (since C++20)

Allocates and constructs an object of type `U`.

Given `alloc` is a std::pmr::polymorphic_allocator<T>:

    U* p = alloc.new_object<U>(std::forward<CtorArgs>(ctor_args)...);

is equivalent to

    U* p = alloc.allocate_object<U>();
    try
    {
        alloc.construct(p, std::forward<CtorArgs>(ctor_args)...);
    }
    catch (...)
    {
        alloc.deallocate_object(p);
        throw;
    }

### Parameters

ctor_args | - | the arguments to forward to the constructor of `U`

### Return value

A pointer to the allocated and constructed object.

### Notes

This function was introduced for use with the fully-specialized allocator std::pmr::polymorphic_allocator<>, but it may be useful in any specialization as a shortcut to avoid having to rebind from std::pmr::polymorphic_allocator<T> to std::pmr::polymorphic_allocator<U>, and having to call allocate, construct, and deallocate individually.

Since `U` is not deduced, it must be provided as a template argument when calling this function.

### Exceptions

May throw any exceptions thrown by the call to allocate_object or the constructor of `U`.

### See also

allocate_bytes (C++20) | allocate raw aligned memory from the underlying resource (public member function)
allocate_object (C++20) | allocates raw memory suitable for an object or an array (public member function)
allocate | allocate memory (public member function)
allocate [static] | allocates uninitialized storage using the allocator (public static member function of `std::allocator_traits<Alloc>`)
allocate | allocates memory (public member function of `std::pmr::memory_resource`)

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